1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* Copyright(c) 2024 Intel Corporation. */ 3 #ifndef __CXL_MBOX_H__ 4 #define __CXL_MBOX_H__ 5 #include <linux/rcuwait.h> 6 #include <cxl/features.h> 7 #include <uapi/linux/cxl_mem.h> 8 9 /** 10 * struct cxl_mbox_cmd - A command to be submitted to hardware. 11 * @opcode: (input) The command set and command submitted to hardware. 12 * @payload_in: (input) Pointer to the input payload. 13 * @payload_out: (output) Pointer to the output payload. Must be allocated by 14 * the caller. 15 * @size_in: (input) Number of bytes to load from @payload_in. 16 * @size_out: (input) Max number of bytes loaded into @payload_out. 17 * (output) Number of bytes generated by the device. For fixed size 18 * outputs commands this is always expected to be deterministic. For 19 * variable sized output commands, it tells the exact number of bytes 20 * written. 21 * @min_out: (input) internal command output payload size validation 22 * @poll_count: (input) Number of timeouts to attempt. 23 * @poll_interval_ms: (input) Time between mailbox background command polling 24 * interval timeouts. 25 * @return_code: (output) Error code returned from hardware. 26 * 27 * This is the primary mechanism used to send commands to the hardware. 28 * All the fields except @payload_* correspond exactly to the fields described in 29 * Command Register section of the CXL 2.0 8.2.8.4.5. @payload_in and 30 * @payload_out are written to, and read from the Command Payload Registers 31 * defined in CXL 2.0 8.2.8.4.8. 32 */ 33 struct cxl_mbox_cmd { 34 u16 opcode; 35 void *payload_in; 36 void *payload_out; 37 size_t size_in; 38 size_t size_out; 39 size_t min_out; 40 int poll_count; 41 int poll_interval_ms; 42 u16 return_code; 43 }; 44 45 /** 46 * struct cxl_mailbox - context for CXL mailbox operations 47 * @host: device that hosts the mailbox 48 * @enabled_cmds: mailbox commands that are enabled by the driver 49 * @exclusive_cmds: mailbox commands that are exclusive to the kernel 50 * @payload_size: Size of space for payload 51 * (CXL 3.1 8.2.8.4.3 Mailbox Capabilities Register) 52 * @mbox_mutex: mutex protects device mailbox and firmware 53 * @mbox_wait: rcuwait for mailbox 54 * @mbox_send: @dev specific transport for transmitting mailbox commands 55 * @feat_cap: Features capability 56 */ 57 struct cxl_mailbox { 58 struct device *host; 59 DECLARE_BITMAP(enabled_cmds, CXL_MEM_COMMAND_ID_MAX); 60 DECLARE_BITMAP(exclusive_cmds, CXL_MEM_COMMAND_ID_MAX); 61 size_t payload_size; 62 struct mutex mbox_mutex; /* lock to protect mailbox context */ 63 struct rcuwait mbox_wait; 64 int (*mbox_send)(struct cxl_mailbox *cxl_mbox, struct cxl_mbox_cmd *cmd); 65 enum cxl_features_capability feat_cap; 66 }; 67 68 int cxl_mailbox_init(struct cxl_mailbox *cxl_mbox, struct device *host); 69 70 #endif 71